N, K = map(int, input().split())
mod = 998244353
ans = 0
KN = pow(K, N, mod)
q = [0] * (K + 5)
for x in range(K, 0, -1):
    q[x] = KN - pow(x - 1, N, mod)
    q[x] -= (K - x + 1) * N * pow(x - 1, N - 1, mod)
    q[x] %= mod
    ans += x * (q[x] - q[x+1])
    ans %= mod
    
print(ans)